Image processing apparatus and method

ABSTRACT

An image processing apparatus for deinterlacing and vertical scaling a plurality of initial scan lines includes a control unit, a deinterlacer, a vertical scaler and a buffer. The control unit controls the deinterlacer and the vertical scaler to store parts of the processed scan lines thereof into the buffer according to a scaling ratio factor and a vertical scaling algorithm.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan PatentApplication Serial Number 095117800, filed on May 19, 2006, the fulldisclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to an image processing apparatus andmethod, and more particularly, to an image processing apparatus andmethod in a video output system.

2. Description of the Related Art

A conventional image processing apparatus usually performs deinterlacingand vertical scaling on images. However, in order to performdeinterlacing and vertical scaling, the scan lines of the images have tobe accessed frequently so as to execute interpolation operation.Therefore, the accessing method of the scan lines will influence theperformances of the deinterlacing and vertical scaling.

Since conventional methods of accessing scan lines are unsatisfactory, asame scan line may be accessed and executed repeatedly duringdeinterlacing and vertical scaling thereby causing redundant using ofthe bandwidth.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an image processingapparatus to solve aforementioned problems.

It is another object of the present invention to provide an imageprocessing apparatus which utilizes a control unit to control the accessof the scan lines and prioritize to store the scan lines occupying morebandwidth into a storage unit.

In order to achieve above objects, the present invention provides animage processing apparatus for deinterlacing and vertical scaling aplurality of initial scan lines. The image processing apparatus mainlyincludes a control unit, an accessor, a deinterlacer, a line buffer anda vertical scaler, wherein the control unit is utilized for receiving atleast one scaling ratio factor and a field number parameter; theaccessor is coupled to the control unit for accessing at least one ofthe initial scan lines according to the control of the control unit; thedeinterlacer is coupled to the control unit and the accessor foroutputting at least one corresponding scan line according to theaccessed initial scan lines; the line buffer is coupled to thedeinterlacer for storing at least one of the corresponding scan linesoutputted from the deinterlacer; the vertical scaler is coupled to thecontrol unit, the deinterlacer and the line buffer for performing avertical scaling according to the at least one corresponding scan lineoutputted from the deinterlacer, the corresponding scan line stored inthe line buffer and a vertical scaling algorithm thereby outputting atleast one output scan line; wherein the control unit determines whetherto store the at least one corresponding scan line into the line bufferaccording to the scaling ratio factor and the vertical scalingparameter.

The present invention further provides an image processing method fordeinterlacing and vertical scaling a plurality of initial scan lines.The image processing method includes the following steps: accessing atleast one of the plurality of initial scan lines according to a fieldnumber parameter; utilizing a deinterlacer to output at least onecorresponding scan line according to the accessed initial scan lines;determining whether to store the at least one corresponding scan lineinto a storage unit according to a scaling ratio factor and a verticalscaling algorithm; and performing a vertical scaling according to the atleast one corresponding scan line, at least one of the previously storedscan lines and the vertical scaling algorithm thereby outputting atleast one output scan line.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, advantages, and novel features of the present inventionwill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings.

FIG. 1 shows a block diagram of an image processing apparatus and methodaccording to an embodiment of the present invention.

FIG. 2 a shows a schematic diagram of a scaling process performed by theimage processing apparatus and method according to the embodiment of thepresent invention.

FIG. 2 b shows a schematic diagram of a scaling process performed by theimage processing apparatus and method according to the embodiment of thepresent invention, which follows the process shown in FIG. 2 a.

FIG. 2 c shows a schematic diagram of a scaling process performed by theimage processing apparatus and method according to the embodiment of thepresent invention, which follows the process shown in FIG. 2 b.

FIG. 2 d shows a schematic diagram of a scaling process performed by theimage processing apparatus and method according to the embodiment of thepresent invention, which follows the process shown in FIG. 2 c.

FIG. 3 a shows a schematic diagram of a scaling process performed by theimage processing apparatus and method according to another embodiment ofthe present invention.

FIG. 3 b shows a schematic diagram of a scaling process performed by theimage processing apparatus and method according to another embodiment ofthe present invention, which follows the process shown in FIG. 3 a.

FIG. 3 c shows a schematic diagram of a scaling process performed by theimage processing apparatus and method according to another embodiment ofthe present invention, which follows the process shown in FIG. 3 b.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring now in detail to exemplary embodiments of the presentinvention, which are illustrated in the accompanying drawings, in whichlike numerals designate like elements.

Referring to FIG. 1, an image processing apparatus 30 according to anembodiment of the present invention includes a buffer 31, a control unit32, an accessor 33, a deinterlacer 34, a vertical scaler 35 and astorage unit 36, and the image processing apparatus 30 outputs imagesignals to a display device 90 so as to display images on the displaydevice 90. The present invention may further include a horizontal scaler37 coupled between the vertical scaler 35 and the display device 90 soas to horizontally scale the image signals outputted from the verticalscaler 35 and to output the horizontally scaled image signals to thedisplay device 90. Since the implementation of the horizontal scaler 37is appreciated to those skilled in the art, the detailed descriptionwill not be illustrated hereinafter.

Referring further to FIG. 1 again, in the image processing apparatus 30,one embodiment of the buffer 31 is a frame buffer; the control unit 32controls the operations of the accessor 33, the deinterlacer 34, thevertical scaler 35 and the storage unit 36 in accordance with an imagescaling ratio factor and a field number parameter. The controlling ofthe above-mentioned elements, e.g. accessor 33, under the control unit32 can be implemented by hardware or firmware (software). One embodimentof the accessor 33 is a direct memory access (DMA), and the accessor 33accesses one or more scan lines from the buffer 31 according to thecontrol signals outputted from the control unit 32. The deinterlacer 34outputs a corresponding scan line which is deinterlaced or notdeinterlaced according to the scan lines accessed by the accessor 33.The deinterlacer 34 stores specific corresponding scan lines into thestorage unit 36 according to the control of the control unit 32. In thisembodiment, the specific corresponding scan lines are the scan lineswhich will be executed in the later processing, e.g. deinterlacing andvertical scaling. In addition, the vertical scaler 35 vertically scalesthe scan lines outputted from the deinterlacer 34 and/or the scan linesstored in the storage unit 36 according to the control signals outputtedfrom the control unit 32. The control unit 32 in accordance with thepresent invention may further include a manage unit 321 for managing andupdating the data stored in the storage unit 36 according to the scaleratio factor and a predetermined vertical scaling algorithm. In thisembodiment, the storage unit 36 is a line buffer, which can store atleast one scan line. In an alternative embodiment of the presentinvention, the accessor 33 may access the needed scan lines via anexternal storing device, and hence the buffer 31 may be omitted.

When the image processing apparatus 30 is in operation, the buffer 31receives and temporarily stores a field from an image source, which maybe an odd field or an even field; the control unit 32 sends a signal tothe accessor 33 according to field number parameters so as to controlthe accessor 33 to access at least one scan line from the buffer 31 tobe executed by the deinterlacer 34. After the deinterlacer 34 executesthe scan lines outputted from the accessor 33, the deinterlacer 34generates corresponding scan lines and sends them to the vertical scaler35 for vertical scaling. In addition, the control unit 32 can predictthe scan lines which will be utilized by the vertical scaler 35according to the scale ratio factor and the predetermined verticalscaling algorithm so as to control the deinterlacer 34 to temporarilystore the scan lines, which will be executed in the later processing,into the storage unit 36. Additionally, the control unit 32 sends asignal to the vertical scaler 35, according to the scaling ratio factorand the predetermined scaling algorithm, to control the vertical scaler35 vertically scales the scan lines outputted from the deinterlacer 34and the scan lines stored in the storage unit 36. Furthermore, thecontrol unit 32 can send a signal to the deinterlacer 34 in accordancewith a predetermined deinterlacing algorithm so as to control thedeinterlacer 34 to deinterlace the scan lines outputted from theaccessor 33 and the scan lines stored in the storage unit 36.

Referring now to FIGS. 1 and 2 a to 2 d, they illustrate an imageprocessing apparatus and method according to an embodiment of thepresent invention. In this embodiment, the storage unit 36 cantemporarily store three scan lines, and the vertical scaler 35 is a4-tap filter, however, this is just one embodiment and should not beadapted to limit the scope of the present invention. As shown in FIGS. 2a to 2 d, assuming the rectangle frame F1 contains six scan lines whichare respectively numbered as #1 to #6, wherein the scan lines #1, #3 and#5 designate the non-deinterlaced scan lines generated by thedeinterlacer 34, and the scan lines #2, #4 and #6 designate thedeinterlaced scan lines generated by the deinterlacer 34. The filledscan lines in the rectangular frame F1 designate the scan lines whichwill be re-stored into the storage unit 36 by the vertical scaler 35,e.g. scan lines #2, #3 and #4 as shown in FIG. 2 a. Rectangular frame F2contains a plurality of scan lines numbered as #A to #D hereinafter,generated by vertical scaling, wherein the scan lines #A to #D representthe vertical scaled scan lines generated by the vertical scaler 35, andthe dotted rectangular in the rectangular frame F1 contains the neededscan lines in order to generate the scan lines #A, #B, #C and #D.

Referring to FIG. 2 a, when it is desired to generate the scan line #Ain the rectangular frame F2, the vertical scaler 35 utilizes the scanlines #1 to #4 in the rectangular frame F1 to generate the scan line #Aaccording to a predetermined vertical scaling algorithm, and then thecontrol unit 32 controls the vertical scaler 35 to re-store the scanlines #2 to #4 in the rectangular frame F1 back into the storage unit36. Referring now to FIG. 2 b, when it is desired to generate the scanline #B in the rectangular frame F2, the vertical scaler 35 will readout the scan lines #2 to #4 from the storage unit 36 according thevertical scaling algorithm and the scan line #1 from the buffer 31 so asto generate the scan line #B from the scan lines #1 to #4, and thenagain re-store the scan lines #2 to #4 back into the storage unit 36. Itshould be noted that the vertical scaler 35 does not re-store the scanlines #1 to #3 back into the storage unit 36 because the scan line #1needs not to be generated by the deinterlacer 34 through deinterlacing.Therefore, reading the scan line #1 from the buffer 31 occupiesrelatively fewer bandwidth than re-generating the scan line #4 from thedeinterlacer 34.

Referring now to FIG. 2 c, when it is desired to generate the scan line#C in the rectangular frame F2, the vertical scaler 35 reads out thescan lines #2 to #4 from the storage unit 36 and reads the scan line #5from the buffer 31, and then utilizes the scan lines #2 to #5 in therectangular frame F1 to generate the scan line # C according to apredetermined algorithm. Because the control unit 32 is set to know thatto generate the scan lines #2, #4 and #6 by the deinterlacer 34 occupiesmore bandwidth than to read the scan lines #1, #3 and #5 from the buffer31, the control unit 32 controls the vertical scaler 35 to re-store thescan lines #2 to #4 back into the storage unit 36 rather than to storethe scan lines #3 to #5 back into the storage unit 36. It should benoted that, in the above-mentioned description, if the scan lines #2 to#4 have already existed in the storage unit 36 after the scan lines #A,#B, and #C are generated, i.e. the scan lines #2 to #4 are notoverwritten by other scan line data, the control unit 32 needs not tocontrol the vertical scaler 35 to restore the scan lines #2 to #4 backinto the storage unit 36.

Referring to FIG. 2 d, when it is desired to generate the scan line #Din the rectangular frame F2, the vertical scaler 35 reads the scan lines#2 to #4 from the storage unit 36 and re-reads the scan line #5 from thebuffer 31 so as to utilize the scan lines #2 to #5 to generate the scanline #D according to the vertical scaling algorithm. Because the scanline #5 needs not be generated through deinterlacing, re-reading thescan line #5 from the buffer 31 will not take high bandwidth, and thescan lines #3 to #5 will be re-stored back into the storage unit 36 forlater processing after the scan line #D has been generated.

Referring now to FIG. 3 a to 3 c, in an alternative embodiment of thepresent invention, the vertical scaler 35 can be controlled to re-storethe scan lines #2 to #4 into the storage unit 36 after the scan line #Ahas been generated by the vertical scaler 35 through utilizing the scanlines #1 to #4; the vertical scaler 35 then generates the scan line #Bby utilizing the scan lines #2 to #5 after it reads the scan lines #2 to#4 stored in the storage unit 36 and receives the scan line #5 from thedeinterlacer 34, and then re-stores the scan lines #3 to #5 back intothe storage unit 36; then the vertical scaler 35 generates the scan line#C by utilizing the scan lines #3 to #6 after it reads out the scanlines #3 to #5 stored in the storage unit 36 and receives the scan line#6 from the deinterlacer 34, and then re-stores the scan lines #4 to #6back into the storage unit 36. Unlike the first embodiment, the scanlines #2, #4 and #6 in this embodiment needed to be generated bydeinterlacing are not required to be prioritizedly stored back into thestorage unit 36.

Although the invention has been explained in relation to its preferredembodiments, it is not used to limit the invention. It is to beunderstood that many other possible modifications and variations can bemade by those skilled in the art without departing from the spirit andscope of the invention as hereinafter claimed.

1. An image processing apparatus for deinterlacing and vertical scalinga plurality of initial scan lines, the image processing apparatuscomprising: a control unit for receiving at least one parameter; anaccessor coupled to the control unit for accessing at least one of theinitial scan lines according to the control of the control unit; adeinterlacer coupled to the control unit and the accessor for outputtingat least one corresponding scan line according to the accessed initialscan lines; a storage unit coupled to the deinterlacer for storing atleast one of the corresponding scan lines outputted from thedeinterlacer; and a vertical scaler coupled to the control unit, thedeinterlacer and the storage unit for performing a vertical scalingaccording to the at least one corresponding scan line outputted from thedeinterlacer and at least one of the corresponding scan lines stored inthe storage unit thereby outputting at least one output scan line;wherein the control unit determines whether to store the correspondingscan line into the storage unit according to the parameter.
 2. The imageprocessing apparatus as claimed in claim 1, wherein the parametercomprises a scaling ratio factor and/or a field number parameter.
 3. Theimage processing apparatus as claimed in claim 1, wherein the storageunit is a line buffer.
 4. The image processing apparatus as claimed inclaim 1, wherein the at least one corresponding scan line is generatedby the deinterlacer through performing or without performingdeinterlacing, and the control unit controls the deinterlacer toprimarily store the deinterlaced corresponding scan line into thestorage unit.
 5. The image processing apparatus as claimed in claim 1,further comprising: a horizontal scaler coupled to the vertical scalerfor horizontally scaling the output scan line.
 6. The image processingapparatus as claimed in claim 1, wherein the vertical scaler performsthe vertical scaling according to a vertical scaling algorithm.
 7. Theimage processing apparatus as claimed in claim 6, wherein the controlunit determines whether to store the at least one corresponding scanline into to the storage unit according to the vertical scalingalgorithm.
 8. The image processing apparatus as claimed in claim 1,wherein the control unit is coupled to the storage unit and manages thescan lines storing thereof.
 9. The image processing apparatus as claimedin claim 1, wherein the vertical scaler stores at least one of the scanlines performed vertical scaling into the storage unit according to thecontrol of the control unit.
 10. The image processing apparatus asclaimed in claim 1, further comprising a memory for saving the pluralityof initial scan lines.
 11. An image processing method for deinterlacingand vertical scaling a plurality of initial scan lines, the imageprocessing method comprising the steps of: accessing at least one of theplurality of initial scan lines; utilizing a deinterlacer to output atleast one corresponding scan line according to the accessed initial scanlines; determining whether to store the at least one corresponding scanline into a storage unit according to a parameter and a vertical scalingalgorithm; and performing a vertical scaling according to the at leastone corresponding scan line, at least one of the previously stored scanlines and the vertical scaling algorithm thereby outputting at least oneoutput scan line; wherein the parameter comprises at least one scalingratio factor.
 12. The image processing method as claimed in claim 11,wherein the parameter further comprises a field number parameter. 13.The image processing method as claimed in claim 11, wherein the storageunit is a line buffer.
 14. The image processing method as claimed inclaim 11, wherein the at least one corresponding scan line is generatedby the deinterlacer through performing or not performing deinterlacing,and a control unit controls the deinterlacer to primarily store thedeinterlaced corresponding scan line into the storage unit.
 15. Theimage processing method as claimed in claim 11, further comprising thefollowing step: performing horizontal scaling on the output scan line.16. The image processing method as claimed in claim 11, furthercomprising the following step: storing at least one of the scan linesperformed vertical scaling into the storage unit.